A quarter circle of radius a is centered about the origin in the first quadrant and carries a uniform charge of −Q. Find the x- and y-components of the net electric field at the origin.

Respuesta :

Answer:

[tex]E_x = \frac{2kQ}{\pi R^2}[/tex]

[tex]E_y = \frac{2kQ}{\pi R^2}[/tex]

Explanation:

Electric field due to small part of the circle is given as

[tex]dE = \frac{kdq}{R^2}[/tex]

here we know that

[tex]dq = \frac{Q}{\frac{\pi}{2}R} Rd\theta[/tex]

[tex]dq = \frac{2Q d\theta}{\pi}[/tex]

Now we will have two components of electric field given as

[tex]E_x = \int dE cos\theta[/tex]

[tex]E_x = \int \frac{kdq}{R^2} cos\theta[/tex]

[tex]E_x = \int \frac{k (2Qd\theta) cos\theta}{\pi R^2}[/tex]

[tex]E_x = \frac{2kQ}{\pi R^2} \int_0^{90} cos\theta d\theta[/tex]

[tex]E_x = \frac{2kQ}{\pi R^2} (sin 90 - sin 0)[/tex]

[tex]E_x = \frac{2kQ}{\pi R^2}[/tex]

similarly in Y direction we have

[tex]E_y = \int dE sin\theta[/tex]

[tex]E_y = \int \frac{kdq}{R^2} sin\theta[/tex]

[tex]E_y = \int \frac{k (2Qd\theta) sin\theta}{\pi R^2}[/tex]

[tex]E_y = \frac{2kQ}{\pi R^2} \int_0^{90} sin\theta d\theta[/tex]

[tex]E_y = \frac{2kQ}{\pi R^2} (-cos 90 + cos 0)[/tex]

[tex]E_y = \frac{2kQ}{\pi R^2}[/tex]